An accelerator device controls acceleration state of a vehicle according to a stepping amount of a pedal that is connected to a rotation shaft through a pedal arm. A rotation angle of the rotation shaft is detected, and an open degree of a throttle valve which controls the amount of air drawn into an engine of the vehicle is determined based on the rotation angle.
The accelerator device includes a return mechanism part and a hysteresis mechanism part. A driver of the vehicle steps the pedal in an open direction, and the return mechanism part biases the pedal in a dose direction opposite from the open direction. The hysteresis mechanism part makes a force of stepping the pedal larger than a force of canceling the stepping of the pedal. JP-A-2010-158992 describes a manipulated variable input device having two hysteresis mechanism parts which generate different hysteresis characteristics.
A housing of the manipulated variable input device has an opening corresponding to a movable range of the pedal arm. A seal member is arranged in the opening to restrict a foreign matter from entering the manipulated variable input device. The pedal arm is connected to an end of the rotation shaft that protrudes outward from the housing through the opening.
However, when only the other end of the rotation shaft is supported by the housing as cantilever structure, a direction of force applied to the other end of the rotation shaft may be varied between when the pedal is not operated and when the pedal is operated. In this case, the rotation shaft may be deformed, and the rotation shaft cannot have stable rotation.